When I build software I always do it aligned with a model. The model evolves with the software and in many cases defines the boundaries of what can and can't be done (that is without modifying or breaking it). A good model is one which is simple to understand yet powerful enough to allow the introduction of new features.
A good model makes me happy. If it was developed by me then it will be the first thing I will show when presenting my work. If it is others it will be the first things that will make me appreciate their work. Actually I think so high on the importance of a good model that I have made the mistake of asking my users to learn it too.
Users obviously view the world through their eyes. In places you might recognize several use cases as the same one, your users might see them as completely different cases.
It seems I am not the only one taking this approach. Remember the first days of Android OS. One of the first things they were proud of was: "Everything is an application". Indeed as a Software Engineer the fact that every functionality on top of the operating system is modeled as an application is simple yet powerful. But as a user I always moved uncomfortably in my chair when pressing on the applications button and find the Phone application there. You see, as a user I have a phone device with phone related functions and I have the applications which is an extension to the phone. Finding the phone icon and contacts icon in the applications section confused me. Especially in the early days of Android where the phone application shortcuts was permanent. IPhone OS took a different approach where some of the device functionality was presented to the user as OS features (e.g. Siri,).
On the other hand Java takes a different approach. One example that comes to mind are the Enums introduced in Java 5. Although one can easily implement an Enum (see http://www.javacamp.org/designPattern/enum.html)
they still decided to include it in the language.
What is the correct approach? Taking the first approach, in which the model is generic and it is also introduced to the user, is cheaper and easier to develop. Yet it will produce a less friendly software. So I believe the key consideration here is: Who is your user and will he be able to learn and adapt?
Recently I have started to adopt a hybrid approach. I expose both the general powerful model to the advanced user and a simple domain oriented interface for the average user.
To sum things up I highly recommend (especially for developers) to pay attention to the difference in the point of view of users vs. the model. Moreover, to decide on the correct approach consider both the user nature and your resources.